Leviticus 16:6

2 And the LORD said to Moses: “Tell your brother Aaron not to enter freely into the Most Holy Place behind the veil in front of the mercy seat on the ark, or else he will die, because I appear in the cloud above the mercy seat.

3 This is how Aaron is to enter the Holy Place: with a young bull for a sin offering and a ram for a burnt offering.

4 He is to wear the sacred linen tunic, with linen undergarments. He must tie a linen sash around him and put on the linen turban. These are holy garments, and he must bathe himself with water before he wears them.

5 And he shall take from the congregation of Israel two male goats for a sin offering and one ram for a burnt offering.

6 Aaron is to present the bull for his sin offering and make atonement for himself and his household.

7 Then he shall take the two goats and present them before the LORD at the entrance to the Tent of Meeting.

8 After Aaron casts lots for the two goats, one for the LORD and the other for the scapegoat,

9 he shall present the goat chosen by lot for the LORD and sacrifice it as a sin offering.

10 But the goat chosen by lot as the scapegoat shall be presented alive before the LORD to make atonement by sending it into the wilderness as the scapegoat.

Read all of Leviticus 16